Within the realm of illuminated pushbutton switch usage, specialized applications are emerging requiring inclusion of latching, blinking or remote control functions to be included within the illuminated pushbutton switch housing. Such applications may require depressing the pushbutton switch to initiate a remote action request, activating switch functions from a remote location, energizing or blinking a local or remote display, and resetting the switch state automatically upon remote acknowledgement. Other applications may involve a plurality of illuminated pushbutton switches in differing locations, all controlling the same functions, wherein a switch depressed at one location must change the state of a switch or display at another location. Other applications may need a single illuminated pushbutton switch to cycle through multiple latched states based on signals from either successive switch presses or from a remote source. Nearly all applications require the added safety feature of an automatic reset to a default state after loss of power.
Proposed designs may incorporate local latching and remote release functions through the use of internal electromagnetic holding coils, in some cases together with various electronic or electromechanical means to interrupt the holding coil current locally without remote intervention. Many of the proposed designs that rely upon an internal electromagnetic holding coil suffer from excessive power consumption, excessive heat, sensitivity to shock and physical jarring, electrical spikes, holding coil drop-out on low voltage, and low reliability. The internal holding coil also makes the resulting illuminated pushbutton switch substantially longer and heavier than standard models that do not incorporate a holding coil.
There is, therefore, a need in the art for improved latching and release in pushbutton switches, together with other features.